Precision, Very Low Noise, Low Input
Bias Current Operational Amplifiers
AD8671/AD8672/AD8674
FEATURES
Very low noise: 2.8 nV/√Hz, 77 nV p-p
Wide bandwidth: 10 MHz
Low input bias current: 12 nA max
Low offset voltage: 75 μV max
High open-loop gain: 120 dB min
Low supply current: 3 mA typ per amplifier
Dual-supply operation: ±5 V to ±15 V
Unity-gain stable
No phase reversal
NC
1
–IN
2
+IN
3
PIN CONFIGURATIONS
8
NC
NC
1
–IN
2
+IN
3
03718-B-001
8
NC
NC = NO CONNECT
NC = NO CONNECT
Figure 1. 8-Lead SOIC_N (R-8)
Figure 2. 8-Lead MSOP (RM-8)
OUT A
1
–IN A
2
8
V+
OUT B
03718-B-003
OUT A
1
–IN A
2
8
V+
AD8672
7
PLL filters
Filters for GPS
Instrumentation
Sensors and controls
Professional quality audio
Figure 3. 8-Lead SOIC-N (R-8)
Figure 4. 8-Lead MSOP (RM-8)
OUT A
1
–IN A
2
14
13
OUT D
–IN D
+IN D
OUT A
1
–IN A
2
+IN A
3
V+
4
14
13
OUT D
–IN D
+IN D
GENERAL DESCRIPTION
The AD8671/AD8672/AD8674 are very high precision amplifiers
featuring very low noise, very low offset voltage and drift, low
input bias current, 10 MHz bandwidth, and low power
consumption. Outputs are stable with capacitive loads of over
1000 pF. Supply current is less than 3 mA per amplifier at 30 V.
The AD8671/AD8672/AD8674’s combination of ultralow noise,
high precision, speed, and stability is unmatched. The MSOP
version of the AD8671/AD8672 requires only half the board
space of comparable amplifiers.
Applications for these amplifiers include high quality PLL
filters, precision filters, medical and analytical instrumentation,
precision power supply controls, ATE, data acquisition, and
precision controls as well as professional quality audio.
The AD8671/AD8672 are specified over the extended industrial
temperature range (−40°C to +125°C), and the AD8674 is specified
over the industrial temperature range (−40°C to +85°C).
The AD8671/AD8672 are available in the 8-lead SOIC and
8-lead MSOP packages. The AD8674 is available in 14-lead
SOIC and 14-lead TSSOP packages.
Surface-mount devices in MSOP packages are available in tape
and reel only.
+IN A
3
V+
4
AD8674
12
AD8674
12
TOP VIEW
11
V–
(Not to Scale)
10
+IN C
+IN B
5
03718-B-005
TOP VIEW
11
V–
(Not to Scale)
10
+IN C
+IN B
5
–IN B
6
OUT B
7
9
8
–IN B
6
OUT B
7
9
8
–IN C
OUT C
–IN C
OUT C
Figure 5. 14-Lead SOIC_N (R-14)
Figure 6. 14-Lead TSSOP (RU-14)
Rev. D
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2004–2009 Analog Devices, Inc. All rights reserved.
03718-B-006
03718-B-004
APPLICATIONS
TOP VIEW
6
–IN B
+IN A
3
(Not to Scale)
V–
4
5
+IN B
OUT B
TOP VIEW
+IN A
3
6
–IN B
(Not to Scale)
V–
4
5
+IN B
7
AD8672
03718-B-002
7
V+
TOP VIEW
6
OUT
(Not to Scale)
V–
4
5
NC
AD8671
7
V+
TOP VIEW
6
OUT
(Not to Scale)
V–
4
5
NC
AD8671
AD8671/AD8672/AD8674
TABLE OF CONTENTS
Specifications..................................................................................... 3
Electrical Characteristics, ±5.0 V ............................................... 3
Electrical Characteristics, ±15 V ................................................ 4
Absolute Maximum Ratings ............................................................ 5
ESD Caution .................................................................................. 5
Typical Performance Characteristics ............................................. 6
Applications ..................................................................................... 11
Power Dissipation Calculations ................................................ 11
Unity-Gain Follower Applications ........................................... 11
Output Phase Reversal ............................................................... 12
Total Noise vs. Source Resistance............................................. 12
Total Harmonic Distortion (THD) and Noise ....................... 13
Driving Capacitive Loads .......................................................... 13
GPS Receiver ............................................................................... 14
Band-Pass Filter .......................................................................... 14
PLL Synthesizers and Loop Filters ........................................... 14
Outline Dimensions ....................................................................... 15
Ordering Guide .......................................................................... 17
REVISION HISTORY
12/09—Rev. C to Rev. D
Changes to Features and General Description Sections.......... 1
Changes to Absolute Maximum Ratings Section, Table 3,
and Table 4 ................................................................................ 5
Added Power Dissipation Calculations Section ..................... 11
Updated Outline Dimensions ................................................... 15
Changes to Ordering Guide ...................................................... 17
6/05—Rev. B to Rev. C
Changes to Figure 6 ...................................................................... 1
Updated Outline Dimensions ................................................... 14
Changes to Ordering Guide ...................................................... 16
4/04—Rev. A to Rev. B
Changes to Figure 32.................................................................. 11
Changes to Figures 36, 37, and 38 ............................................ 12
1/04—Rev. 0 to Rev. A
Added AD8672 and AD8674 parts .............................. Universal
Changes to Specifications .............................................................3
Deleted Figure 3 .............................................................................6
Changes to Figures 7, 8, and 9 .....................................................6
Changes to Figure 37.................................................................. 12
Added new Figure 32 ................................................................. 10
Rev. D | Page 2 of 20
AD8671/AD8672/AD8674
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS, ±5.0 V
V
S
= ±5.0 V, V
CM
= 0 V, T
A
= 25°C, unless otherwise noted.
Table 1.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Offset Voltage Drift
AD8671
AD8672/AD8674
Input Bias Current
Symbol
V
OS
∆V
OS
/∆T
–40°C < T
A
< +125°C
–40°C < T
A
< +125°C
Conditions
Min
Typ
20
30
0.3
0.3
+3
+5
+8
+6
+6
+8
120
6000
6.25
7.5
3.5
15
+4.0
–3.9
+3.9
–3.8
±10
Max
75
125
0.5
0.8
+12
+20
+40
+12
+20
+40
+2.5
Unit
μV
μV
μV/°C
μV/°C
nA
nA
nA
nA
nA
nA
V
dB
V/mV
pF
pF
GΩ
MΩ
V
V
V
V
mA
I
B
+25°C < T
A
< +125°C
–40°C < T
A
< +125°C
Input Offset Current
I
OS
+25°C < T
A
< +125°C
–40°C < T
A
< +125°C
Input Voltage Range
Common-Mode Rejection Ratio
Large Signal Voltage Gain
Input Capacitance, Common Mode
Input Capacitance, Differential Mode
Input Resistance, Common Mode
Input Resistance, Differential Mode
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Output Voltage High
Output Voltage Low
Output Current
POWER SUPPLY
Power Supply Rejection Ratio
AD8671/AD8672
AD8674
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Settling Time
Gain Bandwidth Product
NOISE PERFORMANCE
Peak-to-Peak Noise
Voltage Noise Density
Current Noise Density
Channel Separation
AD8672/AD8674
CMRR
A
VO
C
INCM
C
INDM
R
IN
R
INDM
V
OH
V
OL
V
OH
V
OL
I
OUT
PSRR
V
CM
= –2.5 V to +2.5 V
R
L
= 2 kΩ, V
O
= –3 V to +3 V
–12
–20
–40
–12
–20
–40
–2.5
100
1000
R
L
= 2 kΩ, –40°C to +125°C
R
L
= 2 kΩ, –40°C to +125°C
R
L
= 600 Ω
R
L
= 600 Ω
+3.8
+3.7
–3.8
–3.7
V
S
= ±4 V to ±18 V
110
106
130
115
3
dB
dB
mA
mA
V/μs
μs
μs
MHz
100
3.8
nV p-p
nV/√Hz
pA/√Hz
dB
dB
I
SY
V
O
= 0 V
–40°C < T
A
< +125°C
R
L
= 2 kΩ
To 0.1% (4 V step, G = 1)
To 0.01% (4 V step, G = 1)
3.5
4.2
SR
t
S
GBP
e
n p-p
e
n
i
n
C
S
4
1.4
5.1
10
77
2.8
0.3
–130
–105
0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
f = 1 kHz
f = 10 kHz
Rev. D | Page 3 of
20
AD8671/AD8672/AD8674
ELECTRICAL CHARACTERISTICS, ±15 V
V
S
= ±15 V, V
CM
= 0 V, T
A
= 25°C, unless otherwise noted.
Table 2.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Offset Voltage Drift
AD8671
AD8672/AD8674
Input Bias Current
Symbol
V
OS
∆V
OS
/∆T
–40°C < T
A
< +125°C
–40°C < T
A
< +125°C
Conditions
Min
Typ
20
30
0.3
0.3
+3
+5
+8
+6
+6
+8
120
6000
6.25
7.5
3.5
15
+13.8
–13.8
+12.3
–12.4
±20
±30
Max
75
125
0.5
0.8
+12
+20
+40
+12
+20
+40
+12
Unit
μV
μV
μV/°C
μV/°C
nA
nA
nA
nA
nA
nA
V
dB
V/mV
pF
pF
GΩ
MΩ
V
V
V
V
mA
mA
I
B
+25°C < T
A
< +125°C
–40°C < T
A
< +125°C
Input Offset Current
I
OS
+25°C < T
A
< +125°C
–40°C < T
A
< +125°C
Input Voltage Range
Common-Mode Rejection Ratio
Large Signal Voltage Gain
Input Capacitance, Common Mode
Input Capacitance, Differential Mode
Input Resistance, Common Mode
Input Resistance, Differential Mode
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Output Voltage High
Output Voltage Low
Output Current
Short Circuit Current
POWER SUPPLY
Power Supply Rejection Ratio
AD8671/AD8672
AD8674
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Settling Time
Gain Bandwidth Product
NOISE PERFORMANCE
Peak-to-Peak Noise
Voltage Noise Density
Current Noise Density
Channel Separation
AD8672/AD8674
CMRR
A
VO
C
INCM
C
INDM
R
IN
R
INDM
V
OH
V
OL
V
OH
V
OL
I
OUT
I
SC
PSRR
V
CM
= –12 V to +12 V
R
L
= 2 kΩ, V
O
= –10 V to +10 V
–12
–20
–40
–12
–20
–40
–12
100
1000
R
L
= 2 kΩ, –40°C to +125°C
R
L
= 2 kΩ, –40°C to +125°C
R
L
= 600 Ω
R
L
= 600 Ω
+13.2
+11
–13.2
–11
V
S
= ±4 V to ±18 V
110
106
130
115
3
dB
dB
mA
mA
V/μs
μs
μs
MHz
100
3.8
nV p-p
nV/√Hz
pA/√Hz
dB
dB
I
SY
V
O
= 0 V
–40°C <T
A
< +125°C
R
L
= 2 kΩ
To 0.1% (10 V step, G = 1)
To 0.01% (10 V step, G = 1)
3.5
4.2
SR
t
S
GBP
e
n p-p
e
n
i
n
C
S
4
2.2
6.3
10
77
2.8
0.3
–130
–105
0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
f = 1 kHz
f = 10 kHz
Rev. D | Page 4 of
20
AD8671/AD8672/AD8674
ABSOLUTE MAXIMUM RATINGS
Table 3.
1
Parameter
Supply Voltage
Input Voltage
Differential Input Voltage
Output Short-Circuit Duration
Storage Temperature Range
All Packages
Operating Temperature Range
8-Lead Packages
14-Lead Packages
Junction Temperature Range
All Packages
Lead Temperature Range (Soldering, 60 sec)
1
Rating
36 V
V
S
– to V
S
+
±0.7 V
Indefinite
–65°C to +150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
See the Applications section for a related discussion on power.
–40°C to +125°C
–40°C to +85°C
–65°C to +150°C
300°C
Table 4. Package Characteristics
Package Type
8-Lead MSOP (RM)
8-Lead SOIC_N (R)
14-Lead SOIC_N (R)
14-Lead TSSOP (RU)
1
Absolute maximum ratings apply at 25°C, unless otherwise noted.
θ
JA 1
142
120
90
112
θ
JC
44
43
36
35
Unit
°C/W
°C/W
°C/W
°C/W
θ
JA
is specified for the worst-case conditions, that is., θ
JA
is specified for the
device soldered on a 4-layer circuit board for surface-mount packages.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. D | Page 5 of
20
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